The invention relates to a joint mechanism of a knee orthosis or a knee prosthesis having a having a first part and a second part, which is pivotable in relation thereto, and connection means for fastening the joint mechanism on a user of the knee orthosis or knee prosthesis having a locking mechanism, by way of which a pivoting of the two parts relative to one another in the direction of flexion is prevented by means of a positive locking element which is arranged so as to be displaceable on the second part and in the locking state engages in a positive locking manner in a recess associated with the first part.
Knee joints, either for ortheses or prostheses, which are lockable in a specific position, are designated as locking knee joints. There are different embodiments of locking knee joints which predominantly serve the purpose of giving the user of the knee joint as much security as possible. Prosthesis wearers are, in particular, a patient group in which inactive, for the most part geriatric patients are more likely to be present, to whom, when walking and standing, an increased feeling of security is conveyed by a knee joint locked in the extended position. Said group of prosthesis users is not in a position to prevent a sudden, unwanted bending of the joint by means of compensating movements. Locking in the extended position can also be sensible for orthosis users when the musculature system present is not sufficient to hold the leg stable in certain situations.
DE 103 51 916 A1 shows a prosthesis knee joint having an upper part and a lower part fastened thereto by means of a multi-axial joint mechanism. The lower part is always pivotable in an unrestricted manner in the direction of extension, a locking element is provided which holds a secondary valve of a hydraulic damper unit in the open position.
DE 20 2006 007 461 U1 describes a prosthesis knee joint having an upper part and a lower part fastened thereto in an articulated manner. A lockable and unlockable blocking mechanism, which, when locked, prevents a pivoting of the upper part in relation to the lower part, is provided between the upper part and the lower part.
DE 103 11 189 A1 describes an orthopedic aid having parts which are movable in relation to one another and a locking mechanism for locking the two parts in a predetermined relative position and for unlocking the parts to release the movement of the parts with respect to one another. The orthopedic aid is realized, in particular, as an orthosis. An end portion of a joint lower part is provided with a radial recess into which a locking pin, which is mounted on the joint upper part, engages by way of a lower end which is formed so as to complement the recess. At its upper end, the locking pin merges into a cylindrical core which is axially movable in an interior of an electric coil. When current is directed through the coil, the locking pin is pulled upward into the interior of the coil.